Background: Reduced left ventricular (LV) diastolic function can exert significant load to the right ventricle (RV) that can affect RV–pulmonary vascular (PV) coupling. RV-PV can be assessed with the RV length–force relationship (tricuspid annular plane systolic excursion [TAPSE] to pulmonary artery acceleration time [PAAT] ratio). We aimed to determine the correlation between TAPSE:PAAT and LV diastolic function measured using tissue Doppler imaging (TDI) on Day 1 and its relationship with pulmonary haemorrhage.

Methods: A prospective study of 162 infants with a mean±SD gestation and birthweight of 26.6±1.5 weeks & 938±241 grams. TAPSE:PAAT, LV and septal e` and a` waves were measured on Day 1. PAAT was adjusted for heart rate variability by RV ejection time (PAAT:RVET). Correlation between diastolic indices and TAPSE:PAAT was performed. Receiver operating characteristic (ROC) curve was constructed for pulmonary haemorrhage prediction.

Results: There was a significant positive correlation between TAPSE:PAAT and TAPSE:(PAAT:RVET) with TDI indices of LV diastolic function. This relationship remained significant when adjusting for gestation and RV length (all p<0.01). TAPSE:(PAAT:RVET) was lower in infants who developed pulmonary haemorrhage (n=11, 7%): 11 [6–19] vs. 18 [14–23], p=0.02. For detection of pulmonary haemorrhage, a TAPSE:(PAAT:RVET) > 15 on Day 1 resulted in a sensitivity of 77% and a specificity of 67% with an area under ROC curve of 0.77 (0.59-0.95, 95% CI, p=0.02).

Conclusion: Those findings may have important clinical implications in understanding the role of left heart diseases with the evolution of pulmonary haemorrhage and RV-PV coupling in these infants.